In conventional techniques, gold, platinum, palladium, molybdenum and the like are used as Schottky electrodes (see Japanese Unexamined Patent Application, First Publication No. H01-161759). In addition, gold, tungsten, molybdenum, niobium, tantalum, polysilicon, nickel, platinum, tungsten carbide, molybdenum carbide, tantalum carbide, niobium carbide, tungsten silicide, molybdenum silicide and the like are used as Schottky electrodes for p-type semiconductor diamonds (see Japanese Unexamined Patent Application, First Publication No. H01-246867). Moreover, metals having a melting point of 400 to 700° C., such as aluminum, antimony, tellurium and zinc are used as Schottky electrodes (Japanese Unexamined Patent Application, First Publication No. H03-110824).
It is known that platinum can be used as Schottky electrodes provided for diamond Schottky diodes. However, it cannot be said that platinum has good adhesion properties with respect to diamonds and there is a problem in that a contact surface becomes peeled due to an irregularity in an external mechanical pressure. Particularly, in diamond semiconductors, yield is reduced when a diode forming process is performed.
Moreover, it is thought that an irregularity in adhesion properties of electrodes relate to an irregularity in a Schottky barrier height in the electrodes and that this is the reason deterioration occurs in current-voltage characteristics.